1. Field of the Invention
This invention relates to an apparatus for concurrently leveling an attaching suspended ceilings to supporting structures.
2. Description of the Prior Art
Suspended ceilings are common in the building industry. Such ceilings normally include parallel runner bars supported from hangers of adjustable length which are in turn attached in some way to the ceiling joists. The location of the joists varies significantly throughout a single ceiling in order to accommodate other design features such as placement of utilities. Even though the ceiling joist may vary significantly in location, it is desirable, for purposes of appearance, to have the suspended ceiling lie in a single plane rather than follow the joist variations. In order to accomplish this result, it is important to devise a system for accommodating the irregularities in location of the joists, and regardless of the irregularities, to provide a runner system which has a suspended ceiling lying in a single plane.
Many different systems have been devised for attaching suspended ceiling runners to ceiling joists. Perhaps the earliest and most common method of attaching the runners was a wire attached to the joist and passed through a hole in the runner and then appropriately bent to adjust the runner to the desired height. This system, however, was not a rigid construction and slight movements of the runner resulting from the non-rigid construction rendered the system undesirable. One improvement on this prior system is shown in U.S. Pat. No. 3,032,833. This design makes use of a wire attached to the joist or other portion of the ceiling, which then passes through a hole in an L-shaped support. A bolt passes through the bottom of the L-shaped support, and the bolt has a hook on its end for insertion into the runner. This system, however, still does not provide a rigid system, and, furthermore, requires that the holes in the runner exactly accommodate the suspended wire in order to provide attachment.
Substitution of the rigid bolts for the previously used suspending wires is now common and is further illustrated in U.S. Pat. No. 3,708,941. In this patent, however, the rigid bolt is attached to a clip which is then attached to the ceiling runner. This system, however, is not completely rigid and lacks adaptability in that the attachment to the joist is either restricted or else a multiplicity of different attachment devices must be used in order to give the desired adaptability. This is undesirable in that it creates the need for many different parts rather than making use of a single attachment for all different ceiling joist configurations.
In Australian Pat. No. 204,140, rigid hangers are suspended from the joists and then connected to inverted-T runners with the advantage that the suspended hangers are interconnected by stabilizers above the runner in order to provide a rigid system. This design, however, lacks adaptability in that it only provides for one specific type of attachment on the lower side of a ceiling joist. If utilities or the like prevent this attachment at an exact location, then extensive design alterations must be made in order to accommodate the system. In French Pat. No. 1,181,986, an L-shaped member is attached to the lower side of a ceiling joint and the projecting portion of the L-shaped attachment device is attached to an inverted-T runner. Slots are provided in the L-shaped member in order to adjust the height of the inverted-T runner. This system, however lacks adaptability in that different sizes of L-shaped members must be used for significant variations in joist location, and, furthermore, the inverted-T runner must be designed with its connecting portion in a single plane or else the inverted-T runner will not have the bottom portion thereof lying in a plane parallel to the plane of the floor and, consequently, the ceiling suspended therefrom will be undesirable.
In Canadian Pat. No. 741,946, a bolt is attached to the ceiling joist in a manner which allows it to be adjusted up and down to change the height of the ceiling. The bottom of the bolt is attached to a clip for clipping onto an inverted-T runner. This system provides only one type of attachment to a joist on the underneath portion thereof, thereby severely limiting its adapability and, additionally, releasably secures the inverted-T runner in a design that falls far short of being a rigid system. Additionally, the ceiling tile must be cut away at its back edges in order to accomodate the T-runner clip, and this severely restricts the type of ceiling tile that may be suspended by the system.
In U.S.S.R. Pat. No. 259,729, a rigid support is attached to the ceiling joist and has good adaptability even though it requires a plurality of inner-connected pieces for adjustment thereof. The bottom portion of the suspension system, however, requires opposing hooks having a spring-like design for engagement in the upper portion of a very specific type of inverted-T runner. While this system has some adaptability for accommodating different locations of ceiling joists, it is severely restricted in that it will only accommodate one type of T-runner and is therefore not useful in a wide variety of ceiling systems. In French addition Patent No. 70,110, a bottom connection piece for suspension of a T-runner is illustrated in one of its more complex forms. While the system is adaptable with regard to adjustment of the height of the ceiling, the complexity and number of pieces severely limits the adaptability of the system.
In one further embodiment described in the prior art, U.S. Pat. No. 3,390,856 has a clip for attachment to the upper portion of an inverted-T runner and the clip is attached to a flange suspended from a ceiling joist. This system not only fails to provide for adaptability of the upper portion of the system which connects to the joist, but, in addition, requires a critically designed bulbous upper portion of the inverted-T in order to accommodate the clip. Such a requirement severely restricts the adaptability of the system.
In the new and novel attachment device of this invention, the upper portion, with its swivel nature, is highly adaptable and can be attached to any exposed face of a ceiling joist. Regardless of the location of the ceiling joist, the upper portion of the attachment device can be swiveled to readily accommodate it. The bottom portion of the attachment device has, as an integral portion thereof, an inverted-T runner which may be adjusted at any leveling position in order to accommodate any desired height of suspended ceiling tile. The combined teachings of all of the prior known systems do not result in an attachment device with the adaptability and utility shown in the present invention.